The present invention relates to an electronic component mounting apparatus and a method for mounting electronic components onto boards such as printed boards, boards of liquid crystal displays or plasma display panels with the electronic component mounting apparatus.
An electronic component mounting apparatus is generally constituted so as to mount electronic components on printed boards after taking the components from a feed position by using nozzles. According to the prior art method for mounting the components, a posture of the taken component is detected by a recognition device, thereby recognizing the component. A recognition process will be depicted below with reference to the drawings.
FIG. 2 shows an electronic component mounting apparatus provided with a monitoring system for monitoring an operating state of the apparatus. As shown in FIG. 2, the electronic component mounting apparatus has a main body 1, an operation panel 2 and a host computer 3. Unattended operation has been common to improve the efficiency of the apparatus when mounting the electronic components. Component recognition data is required for the mounting apparatus to recognize the electronic components during mounting. The component recognition data was produced and selected by an operator of the mounting apparatus using the operation panel 2 or host computer 3 when a mounting position program was formed.
FIG. 3 is a flow chart of procedures for forming and selecting the aforementioned component recognition data in the mounting apparatus utilizing the conventional mounting method. In mounting the electronic components by the mounting apparatus, the operator manipulates the mounting apparatus as follows.
Referring to FIG. 3, based on an input of the operator, an outside dimension of the electronic component, a count of leads thereof, a pitch of leads thereof, etc., as geometric features of an electronic component to be mounted, are extracted from catalog data in step #41, and stored in the electronic component mounting apparatus.
In step #42, based on input of the operator, a recognition means (algorithm) supposed to be suitable for the electronic component is selected from the various recognition means assigned to the electronic component mounting apparatus. The number of the selected algorithm and the geometric features inputted in the step #41 are registered and stored in the mounting apparatus as component recognition data.
In step #43, the electronic component is recognized with the use of the component recognition data registered in steps #41 and #42.
In step #44, it is decided whether or not the component recognition is acceptable (OK or NO).
When it is decided in step #44 that the component recognition is acceptable, a difference between a normal mounting posture at a mounting position of the component on the board and a detected suction posture of the component is calculated and corrected in step #45.
Next, in step #46, the component is mounted on the board at the corrected mounting position by the mounting apparatus.
Thereafter, in step #47, it is decided whether or not any components to be mounted are left, that is, whether or not a mounting block is a last one. When the mounting block is the last one, the mounting operation is completed. When the mounting block is not the last one, the program returns to step #43 in order to perform the next mounting operation of the component in a next mounting block.
On the other hand, when the component recognition is not acceptable in step #44, the mounting block to which the component belongs is registered as an error block in step #48.
Next, in step #49, the mounting operation of the component in the mounting block is skipped and the program goes to step #47.
In such a manner, based on the data from the teaching process of steps #41 and #42 through the input of the operator, the mounting process in steps #43 to #47 is performed. In the mounting process, the recognition data of the components in the teaching process are used to confirm the component recognition result and when the confirmed result is acceptable, the selected recognition data is used. When the confirmed result is not acceptable, the mounting operation of the component is skipped and the next component mounting operation is performed carrying out a continuous mounting operation.
The prior art mounting method based on the above-described formation/registration method of the component recognition data in the electronic component mounting apparatus has the following drawbacks.
1) In the teaching process of forming/registering the component recognition data in the electronic component mounting apparatus, since the operator identifies and judges the electronic component to be mounted, the component recognition data varies for every operator. As a result, even the same electronic component cannot be mounted with high recognition accuracy.
2) Since only one recognition algorithm is selected and executed for each electronic component recognition by the operator in the mounting process, if a surface color is minutely different among lots of electronic components or the electronic components shine differently due to a gloss difference of the leads, a recognition efficiency is extremely decreased, leading to an increase of wrong recognitions.
Accordingly, an object of the present invention is to provide an electronic component mounting method and apparatus whereby electronic components with the same geometric features can be recognized/mounted with high accuracy and high recognition efficiency without setting an algorithm for every electronic component, thereby greatly decreasing wrong recognitions, while eliminating the need for an operator to set/control component recognition data.
In accomplishing these and other aspects, according to a first aspect of the present invention, there is provided an electronic component mounting method in which an electronic component is taken from an electronic component feed position, a posture of the component is detected, and the component is mounted on a board based on a detected result. The method includes acquiring image data of the component taken from the feed position by a camera, processing acquired image data with a plurality of algorithms for detecting postures of components, and detecting a posture of the component.
According to a second aspect of the present invention, there is provided an electronic component mounting method as defined in the first aspect, further including comparing each detected result related to the posture of the component obtained in the plurality of algorithms with geometric features of the component stored in the electronic component mounting apparatus. The second aspect also includes selecting one result from the detected results and correcting data of a mounting position of the component on the board based on the selected result and mounting the component at the mounting position of the board.
According to a third aspect of the present invention, there is provided an electronic component mounting method as defined in the second aspect, wherein in selecting the one result from the detected results, an area value of the component obtained from an outside dimension of the component is compared with an area value of the component obtained from the detected result of the algorithm, thereby selecting the result of the one algorithm correctly recognizing the geometric shape of the component.
According to a fourth aspect of the present invention, there is provided an electronic component mounting method as defined in the second aspect, wherein in selecting the one result from the detected results, a length of an outline of the component obtained from an outside dimension of the component is compared with a length of an outline of the component obtained from the detected result of the algorithm, thereby selecting the detected result of the one algorithm correctly recognizing the geometric shape of the component.
According to a fifth aspect of the present invention, there is provided an electronic component mounting apparatus in which an electronic component is taken from an electronic component feed position, a posture of the component is detected, and the component is mounted on a board based on a detected result. The apparatus includes a camera for acquiring image data of the component from the feed position and a control unit for processing acquired image data with a plurality of algorithms for detecting postures of components, and detecting a posture of the component.
According to a sixth aspect of the present invention, there is provided an electronic component mounting apparatus as defined in the fifth aspect, wherein the control unit compares each detected result related to the posture of the component obtained in the plurality of algorithms with geometric features of the component stored in the electronic component mounting apparatus, thereby selecting one result from the detected results and correcting data of a mounting position of the component on the board based on the selected result and controls to mount the component at the mounting position of the board.
According to a seventh aspect of the present invention, there is provided an electronic component mounting apparatus as defined in the sixth aspect, wherein in selecting the one result from the detected results, the control unit compares an area value of the component obtained from an outside dimension of the component to an area value of the component obtained from the detected result of the algorithm, thereby, selecting the result of the one algorithm correctly recognizing the geometric shape of the component.
According to an eighth aspect of the present invention, there is provided an electronic component mounting apparatus as defined in the sixth aspect, wherein in selecting the one result from the detected results, the control unit compares a length of an outline of the component obtained from an outside dimension of the component to a length of an outline of the component obtained from the detected result of the algorithm, thereby selecting the detected result of the one algorithm correctly recognizing the geometric shape of the component.
According to the aspects of the present invention, positional data for mounting of an electronic component is calculated and stored based on the posture of the electronic component detected by the recognition process and geometric features of the electronic component held, such as by being stored, in the electronic component mounting apparatus. The algorithm for detecting postures of components is not set for each one of the electronic components of the same geometric features.
As a result, the electronic components can be recognized/mounted with high accuracy and high recognition efficiency, a count of wrong recognitions of components is greatly reduced and the need for the operator to set/control the component recognition data is eliminated.
In the above-described method, when the posture of the electronic component from the feed position, taken by the nozzle or a chuck to be mounted onto the printed board or display panel boards is detected by the recognition process, the image of the electronic component is processed with the use of a plurality of algorithms for detecting postures of components. Each result is then compared with the held, i.e. such as stored, geometric features of the electronic component, and one result is selected from a plurality of results. The data of the mounting position of the electronic component is then corrected based on the selected result.